Re: [PATCH v2 2/5] clk: sunxi-ng: mp: support clocks with just a shift register
flat view
From: Chen-Yu Tsai <wens@kernel.org>
Date: 2026-09-18 03:51:42
Also in:
linux-arm-kernel, linux-clk, linux-sunxi
On Fri, Sep 18, 2026 at 6:39 AM Andre Przywara [off-list ref] wrote:
The "mp" clock models a mod clock with divider and a shift field. At least one clock in the Allwinner A523 features just a power-of-2 divider field, so support an initialisation of the clock without providing an actual divider field.
Please just use the single divider clock type instead. It properly supports power-of-2 dividers. ChenYu
quoted hunk ↗ jump to hunk
Add a check whether the "width" field is 0, and skip the divider handling in this case, as the GENMASK macro will not work with a zero length. Signed-off-by: Andre Przywara <andre.przywara@arm.com> --- drivers/clk/sunxi-ng/ccu_mp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)diff --git a/drivers/clk/sunxi-ng/ccu_mp.c b/drivers/clk/sunxi-ng/ccu_mp.c index 7cdb0eedc69b5..3896cb94bf733 100644 --- a/drivers/clk/sunxi-ng/ccu_mp.c +++ b/drivers/clk/sunxi-ng/ccu_mp.c@@ -236,9 +236,11 @@ static int ccu_mp_set_rate(struct clk_hw *hw, unsigned long rate, spin_lock_irqsave(cmp->common.lock, flags); reg = readl(cmp->common.base + cmp->common.reg); - reg &= ~GENMASK(cmp->m.width + cmp->m.shift - 1, cmp->m.shift); + if (cmp->m.width) + reg &= ~GENMASK(cmp->m.width + cmp->m.shift - 1, cmp->m.shift); reg &= ~GENMASK(cmp->p.width + cmp->p.shift - 1, cmp->p.shift); - reg |= (m - cmp->m.offset) << cmp->m.shift; + if (cmp->m.width) + reg |= (m - cmp->m.offset) << cmp->m.shift; if (shift) reg |= ilog2(p) << cmp->p.shift; else --2.43.0